Apparatus for mixing and gunning slurries



Nov. 22, 1966 D. c. BURKLO APPARATUS FOR MIXING AND GUNNING SLURRIES 2Sheets-Sheet 1 Filed July 12, 1965 INVENTOR.

DONALD C BURKLO ATTORN Y Nov. 22, 1966 D. c. BURKLO APPARATUS FOR MIXINGAND GUNNING SLURRIES Fild July 12. 1965 2 Sheets-Sheet 2 INVENTOR.

DONALD C BURKLO ATTQRNEY United States Patent 3,286,995 APPARATUS FORMIXING AND GUNNING SLURRlES Donald C. Burklo, Columbiana, Ohio, assignorto Kaiser Aluminum & Chemical Corporation, Oakland, Calif., acorporation of Delaware Filed July 12, 1965, Ser. No. 470,967 3 Claims.(Cl. 259169) This invention concerns apparatus for mixing and conveyingslurries.

It is known to mix solid materials, for example cementitious materials,with a liquid, for example water, in a tank to form a slurry and then toconvey this slurry through pipes or hoses to the point of use, forexample to where it is sprayed onto the inside of an open-hearthsteelrnaking furnace, in the case of a slurry made from refractorymaterials.

In the past, it has been the general practice to mix such cementitiousrefractory slurries in a tank by means of internal paddles turning on anexternally driven shaft and then to convey the mixedslurry to the pointof use by means of compressed air fed into the tank. This method ofpaddle mixing and high pressure conveying creates several problems. Forone thing, the mixing tank must be able to withstand relatively highpressures and therefore is constructed of heavy gauge steel or theequivalent. Also, there is the problem of sealing the shaftbearingagainst these high pressures at the point where it passes through thepressurized tank. For these and other reasons,'the industry has beenlooking for a simpler, less expensive, and yet efiicient apparatus formixing and conveying slurries.

According to this invention, there has now been discovered an apparatusfor mixing and conveying slurries which does not require the use ofinternal paddles, high pressures, or sealed tanks. The presentlycontemplated best mode of construction of this apparatus is given in thefollowing description. It will be understood, however, that thisdescription is illustrative and not limiting of the scope of theinvention, the limits of which are defined in the appended claims.

FIGURE 1 is a side elevation view of an apparatus according to thisinvention; and

FIGURE 2 is a plan view.

The apparatus comprises a tank, generally indicated by the numeral 11,which has a cylindrical or tubular side section 12, a flat bottomsection 13 of lesser diameter than tubular portion or casing 12, and aconical bottom section 15 connecting flat bottom section 13 andcylindrical side section 12. Located in the flat bottom section 13 is anoutlet opening 16.

Disposed externally of tank 11 is a pump 17. While any pump adapted tohandle the slurry being mixed is suitable, an air-driven diaphragm pump,such as that made by Ingersoll-Rand Company, has been found particularlysuitable. Since this is a commercially available device, the details arenot shown. Pump 17 is connected to outlet opening 16 in tank 11 byconduit or pipe 19. Located in pipe 19 is shut off valve 20. This valveis not essential to the operation of the apparatus, but is included foremergency ,use in the event that pump 17 or some other part oftheexternal piping system breaks when tank 11 is filled with slurry.

The outlet of pump 17 is connected, through second conduit or pipe 21,to two-way valve 23. Two-way valve 23 can be turned so that the slurryis directed either into a third or gunning conduit or pipe 24 or into afourth or return conduit or pipe 25. Pipe 24 leads through shut-.

off valve 22 to nozzle 26 through which the slurry is projected at thepoint of application. Pipe 25 extends into the top of the tank and has adownwardly extending 3,286,995 Patented Nov. 22, 1966 ice portion 25'which is directed generally tangentially to casing 12 of tank 11 andwhich terminates in discharge opening 27. Preferably discharge outlet 27is so disposed that a stream of slurry discharged from it is directed atconical bottom portion 15 of tank 11.

In this embodiment, the apparatus is suitably mounted on wheels 28 formovement from place to place and is provided with a steering and pullinglever 29.

Located within tank 11 and attached to flat bottom portion 13, is acentral tube or cylinder 31. At the bottom of cylinder 31 are locatedopenings or holes 32 which permit passage of the slurry from tank 11 tooutlet opening 16.

In operating the apparatus of the present invention, tank 11 is filledwith water to a point about half the height H of the tank or, in otherwords, to a point above the junction of conical bottom section 15 withcylindrical side section 12. Valve 23 is then turned to direct fluidthrough pipe 25 and thus recirculate it back to tank 11. Pump 17 is thenturned on and the water circulated through holes 32, outlet opening 16,pipe 19, pump 17, pipe 21, valve 23, pipe 25, and discharge 'outlet 27back into tank 11. The impingement of material discharged from outlet 27on the surface of the water in the tank causes the water in the tank tomove with a circular motion about central cylinder 31. Because ofcentrifugal force, the circulating water is forced to the outside of thetank and rises nearly to the top of the cylindrical wall section 12.Concurrently, the water level near the center of the tank drops. Whenthe water is smoothly circulating, the refractory material to beslurried is dumped into tank 11 and the circulation continued until therefractory material is thoroughly mixed with the water. Generally, thisrequires only a minute or two.

When the slurry is completely. mixed, valve 23 is turned to direct theslurry flow into pipe 24, whence it is carried to the point of use.

While the dimensions of the apparatus can be varied as desired, it hasbeen found preferable for most eifective mixing that certain dimensionalrelationships between the size of difierent parts by preserved. It isconvenient to discuss the size of various parts as related to thediameter D of tank 11 itself.

In the first place, the diameter D of tank 11 can be any size desired,the maximum size depending in part upon the capacity of pump 17. It hasbeen found that a pump with a capacity of gallons per minute at a totalhead of 50 p.s.i. is suitable for a tank of 42 inches diameter.

The height H of the tank should be at least as great as the diameter D.The diameter, c, of the flatbottom section 13 is preferably from about0.2D to about 0.6D. The line of junction between the cylindrical sidesection 12 and the conical bottom section 15 preferably is at a distanceof from about 0.2D to about 0.6D above the bottom of tank 11. Thediameter, d, of central cylinder 31 is preferably from about 0.1D toabout 0.5D. However, the diameter, d, of central cylinder 31 is nogreater than the diameter, 0, of the flat bottom portion 13 so that,preferably, there will be a portion of the flat bottom outside thecentral cylinder.

It has been found that when these proportions are observed, good,thorough mixing action is obtained in the apparatus. While it is notdesired to be bound by any theory, it is believed that the downwardlyand tangentially directed stream of fluid from discharge outlet 27, uponstriking the surface of the liquid in tank 11, not only causes a rotaryor swirling motion about the vertical axis of the tank, but also, due toits downwardly directed component, causes rotation of the fluid in avertical plane through the center of the tank. This combination of avertical swirling motion, together with the rotation about the verticalaxis of the tank, is believed to cause a spiral sure tanks.

motion within the fluid which results in exceptionally good mixingaction.

While the height of central cylinder 31 can be varied as desired, itwill conveniently be greater than the height to Which water is initiallyfilled in the tank. In the pres ently described embodiment of thisinvention, it extends nearly to the topof or is of substantially thesame height as tank 11. Central cylinder 31 is conveniently covered orclosed at the top, as illustrated, so as to prevent par ticles ofrefractory material from falling into the interior of this cylinder. 7

Although the apparatus has been described as operating with a pumpdriven by compressed air, it will be understood that any other source ofpower can be used and that any pump capable of handling the slurry to beprepared can be used. Similarly,-the pipes used are of a size adequateto carry the slurry involved, 2-inch pipe being found quite adequatewith a common, commercially available refractory slurrymix. Again, holes32 in the bottom of central cylinder 31 are large enough to pass thelargest solid particles contained in the slurry. Thus, four slots %-inchhigh x 8 inches long spaced equally about the bottom circumference ofcentral cylinder 31 have been found to be effective.

Any suitable materials of construction, for example steel, can be usedin making the tank and associated'parts.

It is an advantage of this apparatus that the tank can be made of athinner gauge of metal than required for pres- Conveniently, pipes 24and 25 are of flexible material, for example rubber.

Having now described the invention, what is claimed is: 1. Apparatus formixing and gunning a cementitious slurry comprising: a mixing tankhaving a tubular Wall section, a flat bottom section, a conical bottomsection joining said fiat bottom section to said tubular wall section,acentrally disposed vertical tube attached to said fiat bottom section,and an outlet opening located in the bottom of the tank within saidcentrally disposed vertical tube, saidtube having apertures adjacentthe. bottom of the tank to provide passageways from the tank to theoutlet opening; first conduit means connecting said outlet opening tothe inlet of a pump; second conduit means connecting the outlet of saidpump to the inlet of a two-way valve having two outlets; third conduitmeans connecting "one outlet of said two-way valve to a dischargenozzle;

the tank, a conical bottom section joining said flat bottom portion tosaid cylindrical wall section, said conical section meeting saidcylindrical section at a distance of from- 0.2 to 0.6 times the diameterof the tank above the bottom of the tank, the total height of the tankbeing-at least equal to the diameter of the tank, a centrally disposed,vertical cylinder having a diameter of from 0.1 to 0.5

times the diameter of the tank, said cylinder being attached to the fiatbottom portion of the tank, and an outlet open ing located within saidvertical cylinder, said vertical cylinder having apertures adjacent thebottom of the tank to provide passageways from the tank to the outlet;first conduit means connecting said outlet to the inlet of'a pump;second conduit means connecting the outlet of said pump to the inlet toa two-way valve having two outlets; third conduit means connecting oneoutlet of said two-way valve to a nozzle; fourth conduit means connected to the second outlet ofsaid two-way valve and terminating in anopening, said opening being directed downwardly and tangentially intosaid tank.

3. Apparatus according to claim 2 wherein said discharge opening isdirected at a point on said conical bottom section.

References Cited by the Examiner UNITED STATES PATENTS 1,531,594 3/1925Carozza 259-148 i 2,316,705 4/1943 'Morgan et a1. 259146 2,660,41511/1953 Hawes 259- 2,664,277 12/1953 Davies 259-l6l WALTER A. SCHEEL,Primary Examiner. R; W. JENKINS, Assistant Examiner.

1. APPARATUS FOR MIXING AND GUNNING A CEMENTITIOUS SLURRY COMPRISING: AMIXING TANK HAVING A TUBULAR WALL SECTION, A FLAT BOTTOM SECTION, ACONICAL BOTTOM SECTION JOINING SAID FLAT BOTTOM SECTION TO SAID TUBULARWALL SECTION, A CENTRALLY DISPOSED VERTICAL TUBE ATTACHED TO SAID FLATBOTTOM SECTION, AND AN OUTLET OPENING LOCATED IN THE BOTTOM OF THE TANKWITHIN SAID CENTRALLY DISPOSED VERTICAL TUBE, SAID TUBE HAVING APERTURESADJACENT THE BOTTOM OF THE TANK TO PROVIDE PASSAGEWAYS FROM THE TANK TOTHE OUTLET OPENING; FIRST CONDUIT MEANS CONNECTING SAID OUTLET OPENINGTO THE INLET OF A PUMP; SECOND CONDUIT MEANS CON-